Postgres: Return tables with hyphenated schemes

[zuchka]

What this PR does / why we need it:

This issue only impacts the FROM select box when using the Postres data source plugin's query builder.

If you have a schema with a hyphen in it (i.e., test-schema), any associated tables will not get populated in the query builder. The linked issue describes the situation well, and the suggested fix 😄

to test, add a schema with a hyphen, add the schema to your search path, and then add a table to that schema:

CREATE SCHEMA "test-schema";
ALTER ROLE youruser SET search_path = "test-schema","public";
CREATE TABLE "test-schema".test(id bigint);

as is, the table will not appear in the query builder

Which issue(s) this PR fixes:

Fixes #19743

Special notes for your reviewer:

[zoltanbedi]

Thanks for fixing these issues @zuchka. I've tried this out and it works well.

[thall]

Ohh that old issue! Thanks! 😄